Method of honing piston rings



SePt- 18, 1956 K. EvAsHEvsKl 2,763,106

METHOD OF' HONING PISTON RINGS ff 65"/ V E f I Mga?? Gttorneg Sept. 18, 1956 K. EvAsHEvsKx 2,763,106

METHOD oF HoNING PIsToN RINGS Sept. 18, 1956 K. EvAsHl-:vsKl 2,763,106

METHOD OF HONING PISTON RINGS Filed May 3l. 1951 3 Sheets-Sheet 3 Gttornegs United States Patent lWETHOD F HGNTNG PISTON RINGS Kenneth Evashevski, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May s1, 1951, serial No. 229,119

`11 claims. (ci. 51-289) This invention relates to a method of and an apparatus for iinishing the exterior surfaces of piston and other similar split rings and has particular relation to a novel method of and an apparatus for nishing such surfaces by the use of a cylindrical honing or other abrading tool.

An object of the invention is to obtain a more uniform radial pressure or pressure pattern for split piston rings employed in the cylinders of internal combustion engines and for other purposes. It is proposed to attain such improved pressure pattern by a novel method of and apparatus for the employment of honing and other abrasive tools, Such tools may be used in practicing the process first to rapidly remove the rough spots and humps found on the exterior surfaces of the rings and later to more slowly but more perfectly form the final finished surfaces by permitting the rings to expand Within the abrading tool. The final finishing operation is performed by relatively rotating and reciprocating the rings and the abrading tool at a cutting or abrading rate which is lower than that employed in performing the iirst part of the finishing operation.

When the rings are abraded by relatively rotating and reciprocating the rings and the abrading tool it will be apparent that the exterior surfaces of the rings will be covered by scratch marks disposed obliquely with respect to the axis of the tool and half of which slope in one direction and half in the other. For example, if a ring is projected into an abrading tool and reciprocated with respect to the abrading tool then the scratch marks on the ring will be parallel to the axis of the tool. If at the same time the ring is moved in one direction it is also rotated then the scratch marks will be spiral in form and will be disposed obliquely with respect to the axis of the tool. When the ring is moved in the opposite direction but rotated in the same direction then the Scratch marks on the exterior surface of the ring will also be of spiral form but will slope in the opposite direction. Hence rotation in one direction and reciprocation in opposite directions will cause the exterior surface of the ring to be covered with obliquely disposed scratch marks that intersect one another.

1f the length of stroke of the reciprocating movement between the abrading tool and the ring is long during a rough finishing operation and short during a final finishing operation then if the relative rate of rotation between the abrading tool and the rings is not changed, the obliquely disposed and intersecting Vscratch marks formed on the rings during the rough finishing and iinal finishing operations will slope differently. The slope of the scratch marks during the nal finishing Aoperation will be much greater than it will be during the rough finishing operation.

It has been found to be desirable to prevent extreme differences in the slope of the scratch marks made on `the rings during the rough finishing and the final finishing operations. It is therefore proposed during the rough iinishing operation to relatively reciprocate the Vrings and the abrading tool throughout a long stroke and Iat one rate of rotation 'and 'duringthe final finishing operation to relatively reciprocate the vrings Vand the abrading tool throughout a short stroke and at a llesser number of revolutions per minute.

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It is apparent that by properly controlling the relation between the length of stroke and the rate of rotation in both the rough iinishing and the final finishing operations the slope of the obliquely disposed scratch marks can be made to be the same or to vary to any desired extent.

For a better understanding of the invention reference may now be had to the accompanying drawing, in which:

Figure l is a fragmentary side elevational View of a honing machine employed in practicing the invention. Certain parts of the machine are broken away to better illustrate certain mechanisms within the machine.

Figure 2 is a diagrammatical plan View of a loading fixture which may be employed in practicing the invention. l'n Figure 2 certain parts of the structure are likewise broken away to better illustrate certain internal parts that are employed in operating the fixture.

Figure 3 is a fragmentary View partly in longitudinal section and partly in elevation of a part of the machine illustrated by Figure l. Figure 3 illustrates the honing cylinder employed in the machine lwith an arbor containing a stack -of rings projecting within the honing cylinder, and a part of the support for the arbor.

Figure 4 is a fragmentary cross-sectional view of the honing cylinder and arbor taken substantially in the plane of line 4 4 on Figure 3.

Figure 5 illustrates a part of the driving mechanism employed in relatively rotating the abrading tool and arbor at various rates of rotation, at various strokes per minute and at various lengths of stroke. Figure 5 is taken substantially in the plane of line 5-5 on Figure 1.

Figure 6 is a plan view taken substantially in the plane of line 6-6 on Figure 5.

Figure 7 is a fragmentary cross-sectional view illustrating a part of a one-way clutch employed in the driving mechanisms illustrated by Figures 5 and 6.

The structure disclosed by Figure 1 includes a machine frame or support 1i) to the upper front part of which a hydraulic kcylinder 11 is secured. The cylinder 11 is adapted to contain `a piston 12 which projects through the lower end thereof and the lower end -of which is adapted to support a honing cylinder or abrading tool indicated a-t 13. The honing cylinder 13 may be of any well-known construction but .as diagrammatically illustrated by Figure V3 the cylinder 13 comprises a cylindrical housing 14 `in which a plurality of longitudinally disposed slots 16 are formed around the periphery thereof. These slots are adapted lto receive radially movable supports indicated at 17. The inner surfaces ofthe supports 17 are recessed as is indicated at 18 for the purpose of receiving and supporting honing or abrading stones indicated at 19. Rings 2-1 and 22 are adapted to be positioned in slots 23 formed in opposed relation tto one another in the opposite ends of the bars 17 for properly positioning the bars Vwith respect to vone another. rl`he bars 17 and the stones 19 are radially movable with respect to one another by hydraulic or other suitable means. Such movement may be brought about in any suitable manner as by the employment of 'a fhydraulic valve mechanism 24 which is secured upon the upper end of a shaft 26 which projects upwardly through the end wall of the .cylinder 11 and on the lower end of which the piston 12 is rigidly secured. The lower end of the shaft 26 which projects through and beyond Vthe piston 12 also supports suitable actuating means 27 which is mounted on the upper end of the honing cylinder 13 and which actuates the .bars 17 in response to the force derived from hydraulic liuid which is received from the valve 24 through ducts formed in .the interior of the ,rod 26.

The honing cylinder 13 also -is Aadapted to be reciproca'ted by uid under pressure introduced into and exhausted from Vthe interior of the cylinder 11. The iiuid so supplied and so exhausted actuates the piston 12 within the cylinder 11 in such manner that the movement of piston reciprocates the honing cylinder 13 which is supported by the piston 12 through the lower end of the shaft 26. A suitable valve actuating mechanism forming forming a part of the hydraulic cylinder assembly is located within the machine and is associated with a control panel indicated at 28. This valve mechanism controls the supply and exhaust of liuid to and from the hydraulic cylinder indicated at 11. The operator of the machine may operate the valve mechanism by actuating the control panel 28 and in such manner as to vary the number of strokes per minute and the length of each stroke of the piston 12 throughout a considerable range. It is generally preferred to control and operate the mechanism in such manner that the number of strokes per minute which the piston 12 makes within the cylinder 11 will be greater when the stroke of the piston 12 is relatively short than when the stroke of the piston 12 is longer. It will be apparent that the number of strokes per minute and the length of stroke of the honing or abrading tool 13 will be the same as the number of strokes per minute and the length of stroke of the piston 12 which supports the honing tool.

The honing tool 13 also may be rotated at dierent speeds and simultaneously with the reciprocation thereof at diierent numbers of strokes per minute and at diierent lengths of stroke. Such rotation of the honing tool 13 may be brought about by rotating the shaft 26 while the piston 12 is employed in reciprocating the shaft 26.

The mechanism for rotating the shaft 26 comprises a gear 29 which is secured rigidly to the shaft 26 within a gear housing indicated at 31. The gear 29 and the housing 31 moves upwardly and downwardly with the shaft 26 as does the valve mechanism 24 located upon the shaft 26 above the housing 31. The housing 31 projects into the supporting frame 1G of the machine through a slot formed in the front wall 32 of the frame and there encloses a gear 33 which is provided with teeth adapted to mesh with the teeth of the gear 29. The gear 33 is slidably mounted on the splined exterior surface of a shaft 34 which projects through openings formed in the upper and lower walls of the housing 13 and which is adapted to be rotatably driven for driving the gears 29 and 33 as the housing 31 and the gears 29 and 33 move in response to the operation of the piston 12. The shaft 34 has bearings in the frame 10 at the upper and lower extremities thereof and the upper end of the shaft projects from the frame and into an angle gear drive housing indicated generally at 36. Projecting laterally from the housing of the driving gear mechanism 36 is a shaft 37 which is employed in driving the shaft 34 through the gear mechanism 36. The shaft 37 supports a multiple V-belt driven pulley 38 adapted to receive a belt 39 and a pair of belts 41. The belts 41 are employed in driving the pulley 38 at high speed or at a larger number of revolutions per minute, whereas the belt 39 is employed in driving the pulley 38 at low speed or at a lower number of revolutions per minute. The belts 41 extend below the drive pulley 31 and there operatively engage a smaller multiple V-belt drive pulley indicated at 42. The pulley 42 is adapted to be driven through an overrunning clutch indicated at 43 by a drive shaft 44 of a motor indicated at 45. The overrunning clutch 43 is of any well-known type, as for example, a clutch such as A,that illustrated in Figure 7.

The clutchrillustrated in Figure 7 comprises an outer driving member adapted to be secured to the pulley 42 and an inner driving member 47 adapted to be secured to the shaft 44. Between the members 46 and 47 is formed an annular channel indicated at 48 adapted to receive and to be practically filled by a plurality of cam members 49 which are disposed in parallel relation to one another and to theaxis of the shaft 44. The cam members 49 are resiliently supported with respect to one another by a spring indicated at 51 and in such manner that the cam members all will be resiliently supported in the same relative position to the driven and driving members indicated at 46 and 47 respectively. In the structure disclosed by Figure 7, when the driving member 47 rotates in a counterclockwise direction, it will be apparent that the cam members 49 will be frictionally wedged between the members 47 and 46 to rotate the member 46 in the same direction the member 47 is being rotated. However, in the event the rotation of the member 47 is discontinued and the member 46 continues to rotate in a clockwise direction, it will be apparent that the frictional driving engagement of the cam members 49 will be rendered inoperative by the rotation of the cam members 49 by the member 46, into positions in which they will not be wedged between the driven and driving members 46 and 47 respectively. It will be apparent therefore that the shaft 44 may be made to drive the pulley 38 through the belts 41 when the motor 45 is operating and that the pulley 38 may be made to operate in the same direction but at a diierent speed when the motor 45 is stopped.

The pulley 38 is also adapted to be driven but at a lower speed than before by the V-belt 39 which projects laterally from the pulley 38 and into operative engagement with a V-belt pulley indicated at 52. The pulley 52 is likewise supported by a second overrunning clutch 53 which may be similar or identical to the overrunning clutch 43 in all essential respects. The driving member of the overrunning clutch 53 is adapted to be driven by a shaft 54 which projects at right angles from a reduction gear mechanism indicated at 56 which is supported and driven by a motor indicated at 57. It will be apparent that if both of the motors 45 and 57 are operating, the pulley 38 will be directly driven through the shaft 44 and the overrunning clutch 43 to drive the pulley 38 at the relatively high speed of operation of the motor 45. During such high speed operation of the pulley 38, thebelt 39 will drive the pulley 52 but the pulley 52 will simply overrun the motor shaft 54 by reason of the overrunning clutch 53. The pulley 38 also will be driven at the high speed operation of the motor 45 in the event the motor 57 is stopped. However, assuming that the motor 57 is operating, the only thing which it is necessary to do in order to operate the pulley 38 at the low speed of operation at which it can be driven by the belt 39 and the pulley 52, is to stop the motor 45. As soon as the motor 45 is stopped, the pulley 38 will slow down until the overrunning clutch 53 directly connects the pulley 52 to the shaft 54 and thereafter the pulley 38 will be operated at a lower speed corresponding to the reduced speed resulting from the operation of the reduction gear 56. The motors 57 and 45 are operable in such manner as to drive the pulley 38 at the higer and lower speeds referred to by operating the electrical contacts associated with the control panel indicated at 28. The shaft 26 may be operated by the pulley 38 at either of the two speeds referred to, through the gear mecheanism 36, the splined shaft 34, the intermeshing gears 29 and 33. It will be apparent that While this may be done during the reciprocation of the gear housing 31 and in response to the reciprocating operation of the piston 12, the shaft 26 also may be driven at the different speeds referred to without reciproeating the shaft 26.

The reciprocation and/ or rotation of the abrasive tool 13 may be employed for finishing the exterior surface of a stack 58 of split piston rings indicated individually by the numeral 59. The stack of rings 58 may be supported upon the exterior surface of an arbor 61 which is adapted to be removably supported by an arbor support or pedestal indicated generally by the numeral 62. The support 62 has parallel guides 63 secured in parallel relation to one another on the lower extremities of a spaced pair of support legs indicated at 64.

arcaico The guides 63 are adapted to be movable in guideways formed in parallel relation to one another within the upper surface of a bed plate 66 which is supported by a lower part of the frame 10. It will be apparent that by elevating the piston 12 in the cylinder 11, the honing tool 13 may be raised to such an extent that the arbor 61 and the support 62 may be moved laterally upon the guide rails 63 and the bed plate 66 to positions at one side of the path of movement of the honing tool 13, thereby making it possible to easily remove the arbor l61 from the support 62 or for any other purpose desired. The base of support 62 may of course be secured in any desired position by tightening the guide rails 63 within the guideways in the plate 66, by any suitable tightening means, not shown.

The arbor 61 comprises an outer cylindrical member 67 having an outer cylindrical or other surface adapted to be disposed within the stack of piston rings indicated at 58. The maximum diameter of the cylindrical member 67 is adapted to be somewhat less than the diameter of the inner cylindrical surface of the piston ring stack indicated at S, to provide a clearance of a few thousandths of an inch indicated by the line 68. The clearance referred to and indicated at 63 is provided between the cylindrical member 67 and the ring stack 58 so that the rings can be contracted to the desired extent without engaging the exterior surface of the member 67 to such an extent as to deform the exterior surface of the ring stack. The lower extremity of the member 67 is recessed and threaded in such manner that a ring indicated at 69 can be tightened upon the lower end of the member 67 against an annular shoulder 71 with which the member 67 is provided. The ring 69 has an annular ange 72 adapted to project around the exterior surface of the member 67 above the shoulder 71, to support the lower extremity of the stack of rings indicated at 58. The diameter of the outer surface of flange 72 and the ring 69 is less than the diameter' of the exterior surface `of the stack of rings indicated at 5S. The upper extremity of the member 67 is provided with a ring 73y having a similar flange 74 adapted to engage the upper extremity of the ring stack 58. The ring 73 is `adapted to be slidably disposed upon a reduced end 76 formed at the upper extremity of the member 67 and is movable for the purpose of clamping the rings in the ring stack 58 rigidly with respect to one another or for releasing the rings if such is desired.

The upper extremity of the member '67 is provided with a plurality of radially disposed openings indicated at 77 in which securing pins 73 are adapted to be rigidly mounted. The inner ends of the pins 78 are adapted Yto project inwardly with respect to the inner surface of the member 67 for the purpose of engaging circumferentially and axially disposed bayonet slots 79 which are Vformed inwardly of and around the end of a collar 81 forming an outer part of the universal joint indicated generally at 82. The universal joint S2 forms the extreme upper end of a support 62 to which the mandrel or arbor 61 is secured by operation of the pins 78 and the bayonet slots 79. The arbor 61 may be secured to or releasedpfrom the support 62 by rotating the arbor and the pins 78 in the circumferential parts of the bayonet'slots 79 thus releasing the pins 7S so that the arbor 61 may be removed by moving the pins 7S through the axially disposed parts of the bayonet slots 79.

The collar 81 is provided with spaced oppositely disposed and downwardly projecting lugs which are indi- Icated'at 83 and which are adapted to be secured by oppositely disposed pins 84 to a block 86 which forms the intermediate member of the universal joint indicated at 82. The block 86 is also adapted to be connected by vpins indicated in dotted lines at 87 to a similar spaced pair of lugs indicated at 8S which project upwardly from 'the end of a supporting shaft indicated 4generally at 89. annular clearance indicated at 91 is provided betweenlthe 6. inner surface of the cylindrical member 67 and the upper extremity of the supporting shaft 89 so as to permit the arbor 61 to be angularly movable on the universal joint -82 and with respect to the supporting shaft 89.

The supporting shaft 89 projects downwardly within and in spaced relation to an outwardly disposed sleeve 92 which forms part of a locking mechanism A93 by which the arbor 61 is prevented from rotation with respect to the support 62. The lower extremity of the sleeve 92 -is slidably disposed with respect to the cylindrical interior surface of an outer housing 94 forming Ythe rigid Iand stationary outer part of the support 62. The lower extremity of sleeve 92 is secured in the housing '94 upon 'the inner extremities of studs 96 which are threaded in openings formed in the housing 94 and the ends of which project inwardlypfrom the housing into cam slots 105 formed at intervals around the lower end of the sleeve 92. The cam slots 165 are formed in the sleeve 92 'to provide parallel helical or other spiral formed camr'nihg surfaces and in such manner that rotation of the sleeve 92 will cause the sleeve to vmove axially upon the pins 96 and with respect to the housing 94. The locking 'mechanism 93 is provided with an operating handle 97 which projects from a split ring 98 which may be rigidly secured to the exterior surface of the sleeve 92 by a screw indicated at 99t It will be apparent that rotation of the handle 97 will move the sleeve 92 vertically with respect to the housing 94 and particularly with respect to 'the supporting shaft 89 which is supported inthe lower p'art of the housing 94 on a universal joint similar tothe universal joint indicated 'at 82. y

The interior surface of the upper end of the sleeve 92 is formed in such a way as to provide 'a sloping annular cam surface indicatedat 9i?. As the sleeve "92 i's 'moved downwardly by operation of the handle 97, the cam' 90 is adapted to engage and to move 'inwardly the lower end of each of one or more levers indicated at 80. yEach of the levers 8() is kslidably disposed within a vvertically disposed slot 95 formed radially inwardly with respect to the exterior surface or" the supporting shaft 89. A pin projecting across each of the slots and through an opening 'formed intermediate the ends of each of the levers S0 supports each lever within its slot 95. The upper ends of the levers 80 are adapted to be moved outwardly by engagement between the cam surface '90 and the opposite ends ofthe levers and into radially disposed slots .100 formed in the lower extremity of the cylindrical member 67. Springs 75 secured to the support 89 by screws 70, have ends projecting 'into each 'of the slots 95 behind the lower ends of the levers 80 for the purpose of vreslientllj holding the levers 80 in inoperative positions with respect to the slots 100 unless the levers are moved into the slots 100 by operation of the cam surface 90 on the sleeve .92. It will be apparent that when the levers 80 are so engaged in the slots 100 as is indicated by the dot-and-das'h Iline positions of the levers, that the 'arbor 61 will be prevented from rotation with respect to the support "62 and the supporting shaft 89 thereof. By sopreventing rotation of the arbor 61 'with 'respect to the support 62, it will be apparent that it will b'e possible for the lower part of .the arbor 61 to move with respect to the support 62 to insure alignment between'the 'arbor and Vthe abrasive tool 13.

The uppe-r extremity of the arbor 61 is -provided with an adjusting mechanism which is indicated generally at 101. The adjusting mechanism 101 is supported upon the upper extremity of an inwardly disposed flange 16?. which is formed on the upper extremity of the cylindrical member 67 and within'the annular recess indicated at 76. The adjusting mechanism 101 includes an 'outwardly flanged sleeve 103 which seats upon the collar -1'02 having an annular centering shoulder 164 projecting u'pwardly therefrom. The upper 'end of the collar` 102 'also has radially disposed :slots 166 which are formed inwardly thereof and which are 'adapted 'to slidably receive a p1u r'alit'y of KLlevers indicated 'at v107. The levers x107 are` supported intermediate the ends thereof on balls 108 adapted to be received in oppositely disposed bearing surfaces formed as spherical depressions in the upper surfaces of the levers 107 and the lower surface of the flanged sleeve 103. The spherical bearing surfaces are formed in such a way as to provide a clearance between the levers 107 and the flanged sleeve 103 to permit angular movement of the levers 107 upon the balls 108. The outer extremities of the levers 107 are adapted to engage the end surfaces of the ring 73 at angularly spaced positions around the ring, so that the ring 73 may be loosened or tightened upon the stack of rings indicated at 58 by movement of the levers upon the fulcrurn means provided by the balls 108.

The opposite ends of the levers 107 are adaptd to be eengaged and to be operated by a ring 109 which is supported by a ball bearing 111 on an annular shoulder 112 formed about the lower end of a shaft indicated at 113. The shoulder 112 of the shaft 113 is rigidly secured to a collar 114 which is mounted for rotation above the block 86 which forms the intermediate part of the universal joint indicated at 82. The upper extremity of the shaft 113 is threaded at 116 for engaging the threaded inner surface of an axially movable sleeve indicated at 117. The lower part of the sleeve 11"/7 is surrounded by a coil spring 118, the upper end of which is adapted to be supported by a ring 119 which rests upon and is supported by a shoulder 121 formed outwardly adjacent the upper end of the sleeve 117. The ring 119 is adapted to project beyond the exterior surface of the spring 118 and within an annular groove 122 formed on the inner cylindrical surface of an outer supporting sleeve indicated at 123. The annular groove 122 is considerably longer than the width of the ring 119 t-o permit the ring 119 and the sleeve 117 by which the ring is supported to move axially with respect to the supporting sleeve 123. The lower extremity of the sleeve 123 rests upon a shoulder 124 vwhich projects inwardly at the lower extremity of a cylindrical opening formed axially within the upper extremity of the flanged sleeve 103 and within which the exterior surface of the supporting sleeve 123 is adapted to be tightly secured. The lower extremity of the supporting sleeve 123 has an inwardly disposed flange 126 adapted to support the lower extremity of the spring 118 and to slidably engage the lower extremity of the sleeve 117.

The upper extremity of the sleeve 117 has a further outwardly projecting flange indicated at 127. The peripheral surface of the flange 127 is adapted to be disposed within and slidably to engage the cylindrical interior surface of the opening in the flanged sleeve 103 in which the supporting sleeve 123 is secured. An annular space 128 is provided between the lower surface of the flange 127 and the upper extremity of the supporting sleeve 123 to permit axial movement of the sleeve 117 with respect to the supporting sleeve 123. Projecting outwardly from the upper parts of the flange 127 are a plurality of radially disposed lugs indicated at 129 which are adapted to be slidably but non-rotatably disposed in slots 131 formed in the upper extremity of the flanged sleeve indicated at 103. Clearances 132 are provided between the lower surface of the lugs 129 and the surfaces forming the inner walls of the slots 131 to permit limited axial movement of the sleeve 117 without having the lugs 129 engage the flanged sleeve 103.

The shaft 113 may be rotated for axially moving the sleeve 117 upon the threaded end 116 of the shaft 113 by rotation of a shaft 133, the upper splined end of which projects within a splined axial opening formed in the collar 114. The shaft 133 projects through enlarged openings 134 and 136 formed in the block 36 and the supporting shaft 89 respectively and terminates between the legs 64 of the support 62. A head member 137 having clutch teeth projecting upwardly from the upper surface thereof is secured rigidly to the lower end of the shaft 133 and is adapted to rotate shaft 133 in response to the manual operation of a lever indicated at 138. The lever 138 has an enlarged end 139 provided with a centrally disposed opening through which the shaft 133 projects and on which the lever is rotatably mounted with respect to the head 137. The enlarged end 139 has clutch teeth formed around the periphery thereof which are complementary to and adapted operatively to engage the teeth formed on the head 137. The enlarged end 139 is normally adapted to be resiliently held in engagement with the head 137 by a spring 141 which is confined between a lower part of the support housing 94 and the upper surface of the enlarged end 139.

It will be apparent that the lever may be turned in either direction for rotating the shaft 133 and that the lever may be operated for turning the shaft 133 in either direction by raising the handle 138 in such a way as to compress the spring 141 to disengage the teeth between the enlarged end 139 and the head 147. When the teeth are so disengaged, the lever may be moved in a direction opposite to that in which it is desired to rotate the shaft 133 and then release for further rotation of the shaft in the desired direction.

It will be apparent that rotation of the shaft 133 will cause axial movement of the sleeve 117 with respect to the threaded end of the Shaft indicated at 116. Axial movement of the sleeve 117 will irst tend to vary the compression of the spring 118 to vary the resilient force exerted by the levers 107 upon the end of the annular ring 73. When the sleeve 117 has been moved in one direction far enough to close the clearance 132, it will be apparent that further rotation of the shaft 133 will cause the levers 107 to positively clamp the rings in the stack S8 between the ring 73 and the ring 69. The shaft may be rotated in this manner until the rings are clamped together securely enough that they may be made to form practically a rigid column or cylinder between the rings 73 and 69.

In Figure 3 the structure is shown with the various parts, latches, and adjustments in positions in which they might be at the end of a honing operation and preperatory to removing a finished stack of rings from the arbor 61. It will be apparent that the latching levers have been removed from the notches by operation of the lever 97 and that the screw 116 has been operated to move the sleeve 117 to open the clearance 132. In such positions the levers 107 are resiliently operated by the spring 118 to hold the rings in frictional engagement with one another but to permit the expansion thereof within the abrading surfaces of the cylindrical honing tool 13. The arbor 61 may be removed from the honing tool 13 at this time by operating the control panel 28 in such manner as to move the honing tool upwardly away from the arbor and until the piston 12 is withdrawn to the limit of its movement within the cylinder 11. However, it may be considered preferable to tighten the rings at this time by rotating the shaft 133 in such manner as to move the sleeve 117 to close the clearance 132. A slight further rotation of the shaft 133 after the clearance 132 is closed will rigidly clamp the rings together in such manner that the rings will not expand when the honing tool 13 is removed. When the honing tool 13 is removed from the arbor 61, then the arbor 61 may be removed from the support 62 by releasing the locking mechanism 93 and by applying a wrench to a pair of ats ywhich are located on opposite sides of the upper extremity of the flanged sleeve 103. The application of a wrench in this manner will rotate the entire arbor with respect to the support 62 and in such manner as to release the pins 78 from the bayonet slots 79. When the arbor is so released it may be removed from the upper part of the support 62 by an upward axial movement of the arbor. Such movement of the arbor will withdraw the splined upper end of the shaft 133 from the splined interior surface of the collar 114 and a splined lever may thereafter 9 be applied to the opening in the collar 114 for manually rotating the shaft 113 to release the rings in the stack 58 to the desired extent. When the rings have been released and expanded by operation of the splined lever refererd to, the rings may be removed from the arbor 61 by removing the threaded ring 69.

The arbor 61 may be reloaded with another stack of rings to be finished by employing the loading tool indicated in Figure 2. The loading tool so illustrated corn'- prises a base plate 151 having an opening 150 formed adjacent one end thereof and in which the middle portion of a semicylindrical clamping member 152 is rigidly secured to the plate 151. A flange 153 projecting outwardly from a middle portion of the clamping member 152 is secured to the plate 151 by bolts indicated at 154. A pair of spaced guides indicated at 156 is secured tothe plate 151 adjacent the opposite end of the opening 150. These guides are adapted to operatively engage guideways formed transversely across a movable clamping member indicated at 157 and intermediate the ends thereof. The clamping member 157 also is secured intermediate the ends thereof to the end of a piston rod -158 which extends through an opening formed in one end of a cylinder 159. The cylinder 159 contains a piston 161 secured to the opposite end of the rod 158 and adapted to operate the rod 158 for moving the movable clamping member 157 in response to differential fluid pressure on opposite sides of the piston 161 within the cylinder 159. Semicylindrical or other suitable surfaces indicated at 162 and 163 are formed in the adjacent surfaces of the clamping members 152 and 157 for the purpose of engaging the exterior surfaces of a stack of rings adapted to be assembled upon the arbor 61.

When it is desired to load the arbor l61 with a new stack of rings it is necessary only to apply a stack containing the correct number of rings to the exterior surface of the cylindrical member 67 and then to close the lower end of the arbor by tightening the ring 69 against the shoulder 71. The piston 161 Within thecylinder 159 is then operated in such manner as to close the clampingjaws 152 and 157, thereby confining the rings in the stack 58 in such manner as to cause the rings to assume the configuration of the cylinder caused by the closing of the semicylindrical surfaces 162 and 163. The rings then may be secured rigidly together upon the arbor 61 by applying a splined crank to the splined interior surface of the collar 114 and by rotating -the crank in such manner as to close the clearance 132, thereby removing the resilienteffect of the spring 11S upon the levers 107. After the clearance 132 is closed, the shaft 113 may be further rotated by operation of the crank referred to, to forcibly move the levers 107 in such manner as to rigidly secure the rings in the stack 58 between the flanges 72 and 7'4 of the rings 69 and 73 respectively. When the rings 69 and 73 are so tightened upon the rings in the stack 58, the rings in the stack will be so positively held together by the end pressure applied and by the frictional force upon the engaging surfaces thereof, that the rings will not appreciably expand when the Vclamping members 153 and 157 are released. The arbor 61 thereafter may be vreleased from the clamping fixture illustrated by Figure 2, by actuating the piston 161 in such a Way as to move the clamping member 157 away from the clamping member 152.

The arbor 61 then may be reinstalled upon the machine by projecting the interior surface ofthe cylindrical member 67 over the upper extremity of the support 62 and in such manner that the upper splined end of the shaft 133 will project into the splined opening in the collar 114. Then by operating the proper means on the control panel 28 the honing tool 13 may be brought down over the exterior surface of the arbor and the stack of lrings indicated at 58 and into the position illustrated by Figure 3.

Further referring to Figure 3, it will be apparent -that fss the stones 19 of the honing tool 13 are pnsitined in such manner that the stack of rings 58 is located approximately midway between the opposite ends of the stones 19. It will therefore b'e -apparent Vthat vthe honing tool 'can be r'eciproc'at'ed throughout a considerable length of stroke before any `of the rings will pass beyond the ends of the stones at either end of the stroke. Such movement of the stones with respect to the rings or even a movement of Vthe vstones beyond the `ends of the rings, may be called a long stroke Af the honing tool 13 with respect to the stack of rings 58. In order to nish the rings in the stack 58 in the shortest possible time, it has been found to 'be desirable to reciprocate the honing tool 1-3 with respect to the rings in the stack 58 throughout the maximum possible length lof stroke during the first .pa-rt of the finishing oper-ation. This may be referred to as the preliminary finishing or long stroke operation.

It h-as also been -found desirable relatively to rotate the rings and the honing tool 413 during this preliminary or long stroke finishing operation. During this preliminary ,finishing operation, the honing tool 13 and stack of rings 5,8 may be relatiyely rotated at aspeed which is considerably higherthan any speed which it is considered desir`able to employ in the nal nfinishing operation on such rings.

For example, in the structure disclosed, it has been found v`possi-ble to `reciprocate the honing tool 13 at about strokes per minute and to rotate the same at about revolutions per minute during the long stroke operation of the honingtool previously referred to.

After the rings have `beenabraded for a time which is considered sufficient to lremove a 'large part ofthe humps and "'rughfspots "from -the exterior surfaces of the rings 'in Wthe, stac'kfSS, then 'the machine may be stopped and th eaft'er adj'stedfandfop'e'rated in `such manner as to 'perform vthe final `ni`shing operation upon Lthe rings in 'the 'stack 58. p Fr such final finishing operation, it has benfound 4desirable 't'o frel'e'as'e the rings within the fabr'ading 'tool '13 so that the rings may radially expand 'into -'resilient 'cnta'ct with the cylindrical interior surfaces forming the 'abra'cling tbol. Toso release the rings, 'it is only necessary togoperat'e 'the lever 138 in'such manner fas to Tretract 'the 'threaded end 116 of the shaft 113 4within the `lsllee`v'e117, thereby openingthe clearances indicatedat132- When thejclearances 7132 are opened, the rings lin the stack 58 will "be resiliently held together by -theoperation of thesp'ring 118 vand to such an extent 1'that the rings and the honing tool 313 .may be relatively rotated. It has been fnnd 'desirable thereafter to relatively l"reciprcycate fthe rings and the honing tool 13 v'throughout"a relatively short stroke which 'may be in the vicinity "o'f approximately half or less than half of the long-stroke operation o'f the two relatively moving parts. It has also been found desirable 'to greatly reduce the `relative 4rotation t-bet'v'v'een 'the hning tool 13 and the rings in the stack 58 during the short stroke operation. Anex'c'ellent ifinal nishing Aoperation can be performed -by reciprocating the honing 'tool 13 `with respect to the 'rings in the sta'c'k `58 vduring lthe short stroke operation at about 96 Ystrokes per minute and rotating the honing tool 13 `with respect :to the Yrings inthe stack 58 at about 7 :revolutiiisper minute. With 'such -ratios vbetween the rotating-'and reciprocatin'g'movements of the honing tool `13, yit will lne-apparent thatfmost of the abrading will be done by relative reciprocating movements between the honing tool "and I`the rings. However, the rings will be rotated by resilient frictional-engagemerit of the surfaces -thereof,enoug'h to continuously present new'honin'g areas to each of the stones of `the tool 13 `during successive reciprocating movements ibetwe'en the tool and the vstack ofring's. v

It will lbe `'apparent'that when *the 'short stroke or final nishing operation referred tohas been completed, the honing vtool ffiiy gbe removed front 4around 'the arbor 61 -and's''c'eess'ive fstackslffrings `'may be applied to the 11 arbor and nished by the machine in the manner hereinbefore described.

l claim: 1. A method of making piston rings which comprises contracting a stack of rings until the exterior surfaces l thereof form a cylindrical surface similar to the cylindrical interior surface of the cylinder in which the rings are to be employed, applying opposed axial forces to the ends of said stack to prevent radial expansion of said rings beyond said cylindrical surface, abrading the exterior surface of said stack of rings so held against expansion and at one abrasion rate, releasing said rings to permit radial expansion of said rings within the limits of said cylindrical surface, and rotatively abrading the exterior surface of said rings While so expanded and at a different abrasion rate and by relative movement about the axis of said rings.

2. A method of making piston rings which comprises contracting a stack of rings until the exterior surfaces of said rings form a continuous cylindrical surface similar to the cylindrical surface of a cylinder in which said rings may be employed, applying opposed axial forces to the ends of said stack to positively secure said rings together to prevent radial expansion of said rings, abrading the exterior surfaces of said rings so held against expansion and at one rate, releasing said rings to permit radial expansion thereof within the limits of said cylindrical surface, and simultaneously applying resilient and opposed axial forces to the ends of said stack of rings and rotatively abrading said rings at a different abrasion rate and by relative movement about the axis of said rings.

3. A method of making piston rings which comprises contracting a stack of rings to form a cylindrical surface, applying opposed axial forces to the ends of said stack of rings to prevent radial expansion of said rings in said stack, rotating and reciprocating said rings so held against expansion and at one abrading rate within and in operative relation to the working surface of an abrading tool, releasing said rings to permit radial expansion of said rings within said tool, and relatively rotating and reciprocating said rings and said abrading tool about the common axis thereof and at a diiferent abrading rate.

4. A method of making piston rings comprising mounting a stack of piston rings upon the exterior surface of an arbor, applying opposed axial forces to the ends of said stack to limit the rotation of said rings relative to said arbor, projecting said rings and said arbor into and in operative relation to the working surface of an abrading tool for linishing the exterior surfaces of said rings, relatively reciprocating said arbor and said abrading tool while relatively rotating said arbor and said abrading tool at one rate, and thereafter relatively rotating said arbor and said abrading tool about the common axis of said arbor and said tool and at a lower rate than said iirst rate.

5. A method of making piston rings which comprises rigidly holding a stack of rings against radial expansion, projecting said stack of rings into and in operative relation to the working surface to a cylindrical abrading tool, relatively rotating said rings and said abrading tool, and thereafter resiliently holding said rings together and allowing radial expansion thereof while relatively rotating said rings and said abrading tool about the common axis thereof and at a lower rate.

6. A method of making piston rings which comprises projecting a conned stack of rings into and in operative relation to the working surface of a cylindrical abrading tool, relatively reciprocating said rings and said abrading tool through strokes of diierent lengths, and relatively rotating said rings and said abrading tool about the common axis thereof and at different revolutions per minute during said different strokes.

7. A method of making piston rings which comprises securing a stack of rings against radial expansion, projecting said stack of rings into and in operativerelation to the working surface of a cylindrical abrading tool, relatively rotating and reciprocating said abrading tool and said rings at a rst number of strokes per minute and a lirst number of revolutions per minute, releasing said rings within said abrading tool, and relatively rotating and reciprocating said rings and said abrading tool about and along the axis of said rings and said abrading tool and throughout a diierent number of strokes per minute and a different number of revolutions per minute.

8. A method of making piston rings which comprises securing a stack of rings against radial expansion, projecting said stack of rings within the interior of and in operative relation to the Working surface of a cylindrical abrading tool, simultaneously rotating and reciprocating said rings and said abrading tool at a first number of revolutions per minute and a first number of strokes per minute and a rst length of stroke, releasing said rings within said abrading tool, and relatively rotating and reciprocating said rings and said abrading tool about and along the axis of said rings and said abrading tool and at a different number of revolutions per minute and a different length of stroke.

9. A method of making piston rings which comprises securing a stack of rings against radial expansion, projecting said stack of rings into and in operative relation to working surface of a cylindrical abrading tool, relatively rotating and reciprocating said rings and said abrading tool at a number of revolutions per minute and a number of strokes per minute and a length of stroke, releasing said rings within said abrading tool and thereafter relatively rotating and reciprocating said rings and said abrading tool about and along kthe axis of Vsaid rings and said abrading tool and ata less number of revolutions per minute and a number of strokes per minute and a shorter stroke.

l0. A method of making piston rings which comprises securing a stack of rings against radial expansion,` pro-r jecting said stack of rings into and in operative relation to the working surface of a cylindrical abrading tool, relatively rotating and reciprocating said rings and said abrading tool at a number of revolutions per minute and a number of strokes per minute and a length of stroke, releasing said rings within said abrading tool, and relatively rotating and reciprocating said rings and said abrading tool about and along the axis of said rings and said abrading tool and at a lesser number of revolutions per minute and a larger number of strokes per minute and a shorter length of stroke.

1l. A method of making piston rings which comprises securing a stack of rings against radial expansion, projecting said stack of rings into and in operative relation to the working surface of a cylindrical abrading tool, relatively rotating and reciprocating said rings and said abrading tool at a number of revolutions per minute and a number of strokes per minute and a length of stroke, releasing said rings for radial expansion within said abrading tool, applying a resilient force at the opposite ends of said stack of rings for frictionally holding said rings together but permitting the expansion thereof within said abrading tool, relatively reciprocating said rings in said abrading tool at a number of strokes per minute and throughout a lengthof stroke and simultaneously relatively rotating said rings and said abrading tool about the common axis thereof and in response to said resilient force and at a lesser number of revolutions per minute.

References Cited in the file of this patent UNITED STATES PATENTS 2,195,056 Wallace Mar. 26, 1940 2,318,837 Connor May 11, 1943 2,422,418 Hutto June l7, 1947 

